[Bug target/87370] [7/8/9 Regression] Inefficient return code of struct values

[hjl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87370

--- Comment #5 from hjl at gcc dot gnu.org <hjl at gcc dot gnu.org> ---
Author: hjl
Date: Sat Sep 29 21:59:59 2018
New Revision: 264716

URL: https://gcc.gnu.org/viewcvs?rev=264716&root=gcc&view=rev
Log:
i386: Use TImode for BLKmode values in 2 integer registers

When passing and returning BLKmode values in 2 integer registers, use
1 TImode register instead of 2 DImode registers. Otherwise, V1TImode
may be used to move and store such BLKmode values, which prevent RTL
optimizations.

gcc/

        PR target/87370
        * config/i386/i386.c (construct_container): Use TImode for
        BLKmode values in 2 integer registers.

gcc/testsuite/

        PR target/87370
        * gcc.target/i386/pr87370.c: New test.

Added:
    trunk/gcc/testsuite/gcc.target/i386/pr87370.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/i386/i386.c
    trunk/gcc/testsuite/ChangeLog